Magnetic clutch



Jan. 2f), 1925- LSZEAHIS E. W. GENT MAGNETIC CLLAITCH Filed Oct. 18, 1921 lul rasata Jan.. 2o, 192s.`

aniram 'stares GENT, OF. MORRISTWN, NEW JERSEY, ASSGNOE T ELECTRIC COMPANY, INCORPORATED, OF NEW' YORK, 1%'. Y., .A

@EPURATION 0F NEW YORK.

MAGNETIC CLUTCH.

`lTo all lwhom it may concern:

Be it known that` I, EDGAR W. Gumy a citizen of the United States, residing at Morristown, in the county of Morris, State of New Jersey, have invented certain new and` useful Improvements in Magnetic Clutches, of which the following is a full, clear, concise, and exact description.

This invention relates to magnetic clutches and more particularly to positive drive mechanism employed in driving switches of thef'type used in automatic telephone systems. An object of the invention is to insure, a mechanism of this character, a more positive engagement of the driving and driven members.

Another object is to enable an adjustment of the normal air gap between the driven member and its operating magnet to be easily accomplished.

One feature of the invention in accordance with the first mentioned object resides in the combination of'a pair of toothed discs, one

of which is adapted to be moved into engagement with the other and an operating magnet having a magnetic circuit including one of said discs but not the other.

Another feature, in -accordance with the second mentioned object, consists in the provision of a pliable back-stop for the driven member, said lback-stop in its preferred einbodiment having a plurality' of radially extending arms which may be readily bent to adjust the air gap.

Referring to the accompanying drawings, Fig. 1 is a side elevation of a rotary sequence switch including apositive drive mechanism in accordance with this invention; Fig. 2 is a perspective view of a driven disc and a back-stop therefor; Fig. 3 is an elevational view, partly in section, of a rotary sequence switch equipped with another type of magnetic clutch in which a back-stop in accordance with this invention is incorporated; Fig. 4 is an enlarged sectional view of the clutch shown in Fig. 3 and Fig. 5 is a perspective view of the driven disc forming a part of the clutch of Fig. 4.

Referring to, Figs. 1 and 2, the continuously rotating shaft 1 supports a driving disc 2 rigidly secured thereto which is provided with ine teeth or corrugations on its beveled edge.

Shaft 3 is suitably journaled at its ends those shown in U.

shown applicativa med'omber is, i921. serial no. 503,432.

on fame 15, and is disposed at right angles to shaft 1..: Mounted thereon are a number of discs each comprising@ pair of skeletonized metallic discs 4 and anintermediate disc of insulating material 5. These disc. are like S. Patent No. 1,127,808, issued to J. N. Reynolds and C. F. Baldwin',

February 9, 1915, but as they are immaterial` to the p resent invention, they are not shown in detail. One or`- more .sets of contact brushes 6 may be provided for cooperating with each disc whereby circuit connections may be established through said brushes when they engage the metallic discs 4. The severaldiscs are held in spaced relation by the insulating separators 7. A vcorrugated centering disc 8 is carried by shaft 3 and is engaged y a spring pressed roller 9 whereby the shaft 3 is always stopped in definite po# sitions.

Thedriven discs 10 is similar to the driving disc 2 in that it is provided with tine teeth or corrugations on its beveled edge, but it differs from disc 2 in that it is flexibly mounted on the shaft 3 by means of the three-armed spider 11. The latter is provided in Fig. 2, which engage longitudinal key slots on shaft 3 whereby said shaft is driven. Disc 10 is preferably secured to the ends' ofthe arms of spider 11 by being spot welded thereto.

The back-stop 13 in the form of a three armed spider is rigidly secured to shaft 3 and serves to normally position the disc 10. The back-stop is not, however, welded or otherwise secured to the disc 10. The spidm` 11 is tensioned to normally pull disc l() against back-stop 13, the arms of which are suiiciently stiff to resist the tension of the spider, but suiciently pliable to admit of being readily bent with pliers. The back or normal position of the driven disc 10 is therefore readily adjustable.

Eleetromagnet 14 is mounted on the frame 15 in juxtaposition to the driven disc 10. The magnetic circuit of magnet 14 includes the pole pieces 17 and 18 and the disc 10. The flexibly mounted driven disc 10 is therefore attracted towards the pole pieces 17 and 18 upon energization of magnet 14 and inasmuch as the attractive force is disposed at only one side of the center of the driven disc, the latter is tilted into engagement with the driving disc instead of being moved with inwardly extendinglugs 12 as' bodily on a line parallel with the axis of shaft 3. When thus engaged, the driven disc 10 together with shaft 3 and the parts mounted thereon are rotated posltively due tothe engagement of the teeth on the discs. Heretofor'e, attempts have been made to provide a positive drive mechanism of the type illustrated in Fig. 1, but 1n each mstance, so far as applicant is aware` the magnetic circuit was arranged to include both the driving and driven discs and passed through the juncture therebetween. It has -f'been found that such an arrangement does not operate eln'ciently due to the fact that a large percentage of the magnetic flux passes from the teeth of one dlsc to the teeth of the other disc along lines normal to the sides of the teeth and that the flux on that account does not tend to hold the discs together, except to a very small extent. Such an arrangement to operate effectively requires a much more powerful magnet than the arrangement here described.

Figs. 3, 4 and 5 illustrate a magnetic clutch in which the shafts to be coupled are in coaxial alignment.

The continuously rotating driving shaft 19, in this instance, is positively coupled with the intermediate shaft through the bevel gears 21 and 22. Intermediate shaft 20 is journaled in ball bearings 23 and 24 which are mounted in the frame 25. One end of shaft 420 is provided with a threaded turned-down portion on which is mounted a toothed clutch member 26. To the last mentioned clutch member there is-secured a cup-shaped stop member 27, preferably of `non-magnetic material, such as brass. The driven shaft 28 is journaled co-axially with shaft 20 in the ball bearings 29 supported within" the clutch member 26 and in other bearings not shown. ,The resilient spider 30 performs the same function as the spider 11 shown in Fig. 2, but in the present instance it is provided with only two arms instead of three. Spider 30 is keyed to a bushing .31 which. in turn,-is secured to shaft 28 and is rotatable therewith.v The spider is secured in place on the bushing by the nut 36 which threads on to the end of shaft 28.

Driven disc 32 is secured to spider 30 by the rivets 33 and is accordingly capable of being tilted in any direction and is provided with two oppositely disposed' integral teeth 34 which are preferably formed b v shearing and pressing as is best shown in Fig. 5.

A? three-armed back-stop 35 of the same character as the back-stop 13 of Figs. 1 and 2 is secured between spider 30 and the nut 36.

Clutch magnet 37 is mounted on frame 25 concentricallv with shaft 20 and is provided with a cylindrical pole-piece 38 and a core member 39 of soft iron.

The magnetic circuit of magnet 37 includes core member 39, clutch member 26,

driven disc 32' and pole ieee 38. Therefore, upon energization o magnet 37, disc 32 is pulled toward clutch member 26 until the disc engages the cup-shaped stop member 27 in which position teeth 34 of the disc engage the teeth of clutch member 26, whereby shaft 28 is driven positively. The cupshaped member 27 being of non-magnetic material may be of such a diameter as to fit quite closely within the cylindrical polepiece 38 without shunting the magnetic circuit. The function of the cup-shaped member is to provide a front stop for disc 32 to prevent the latter rubbing against the polepiece 38.

The normal width of the air gap between disc 32 and. pole-piece 38 may be readily adjusted by bending the arms of back-stop 35 which is provided for that purpose. The back-stop 35 having a three-point engagement with the disc 32, enables the careful adjustment of the air gap for maintaining it of uniform width throughout the circumference of pole-piece 38, so that the disc 32 is attracted bodily without tilting.

What is claimed is:

1. In a positive drive mechanism, a resiliently mounted movable member, an electromagnet for attracting said member, and a pliable back-stop for adjusting the normal 95 position of said member.

2. In a positive drive mechanism, a resiliently mounted movable member, an electromanet for attracting said member, and a bac -stoip for said member comprising a plurality o pliable arms.

3. In a positive drive mechanism,'a resiliently mounted movable member, an electromagnet for attracting said member, and a back-stop for said member comprising a plurality of radially extending pliable arms.

4. In a positive drive mechanism,.a resiliently mounted movable member, an electromagnet for attracting said member, a pliable back-stop for said member, and a rotating member having an axis of rotation at right angles to said first clutch member and adapted to cooperate therewith. Y,

5. In a positive drive mechanism, afrigidly mountedrotatable toothed disc, a resiliently 115 mounted rotatable toothed disc having its axis of rotation at right angles to that of said first mentioned disc, a pliable back-stop for said second mentioned disc, and an electromagnet-for attracting said 'second men- 120 tioned disc into engagement with said first mentioned disc and having va magnetic circuit including said second mentioned disc but not including said first mentioned disc.

6. In a positive drive mechanism, a rigidly mounted rotatable toothed disc, a resiliently mounted rotatable toothed disc having its axis of rotation at an angle to said first mentioned disc, an electromagnet for moving said resiliently mounted disc into opervadapted to be brought into enga ement, an

electroma et for efecting suc engagement, sai electromagnet having a magnetic circuit including one only of said discs and means for adjusting one of said discs with reference to the others.

In witness whereof, l hereunto subscribe my name this 14th day of October A. D.,

EDGAR 'W. GENT. 

